Sure! Here's a simple implementation of an open-world western role-playing game using JavaScript. Please note that this implementation is very basic and may not include all the features you mentioned. Also, keep in mind that this is a text-based game since we are limited to a single HTML file.
To play the game, you can save the code above into an HTML file (e.g., `wildwest.html`) and open it in a web browser. Each time you play, a random event will be shown, and you can select an option by clicking on the corresponding button. The outcome of each choice will be applied, affecting the player's money, health, etc. Additional events and outcomes can be added to enhance the gameplay.